Lubricating oil filter



June 21, 1949. J. A. PlcKARD LUBRICATING OIL FILTER 3 Sheets-Sheet 1 Filed June 1, 1944 June 21, 1949. J. A. PICKARD LUBRICATING OIL FILTER Filed June 1, 1944 3 Sheets-Sheet 2 J. A. PICKARD LUBRICA'I'ING OIL FILTER June 21, 1949.

3 Sheets-Sheet 3 Filed June 1, 1944 engines, but this has Patented June 2 1, 1949 LUBRICATING OIL FILTER Joseph Allen Pickard, Acton,

assignor to ited, llllounslow,

London, England,

The Metafiltration Company Lim- England, a company of Great Britain and Northern Ireland Application June 1, 1944, Serial No. 538,283

2 Claims.

This invention relates to lubricating oil filters and particularly filters adapted for use with, or associated with, internal combustion engines.

The filters associated with engines, and particularly internal combustion engines, operate only during the running of the engine and they depend upon a lubricating oil pump for the pressure necessary to force the oil through them.

As soon as the pump ceases operation, the pressure falls and filtration stops, which is of great disadvantage in the case of engines employed for short runs, as the operation of the filter only begins to be effective in cleaning the oil after the oil in the filter has itself become warm, and this does not usually take place until the engine has been running for some relatively considerable time.

Proposals have been made for warming up such filters by the exhaust from the engine or by the heat of the water employed for cooling the engine, in the case of internal combustion not found favour and in any case would be subject to some limitation as the filter can only purify the oil so long as the engine, and therefore the pump, is running.

According to the invention, between the delivery of the pump and the filter there is included a non-return valve and with the filter there is associated an air chamber in which the level of the oil delivered by the pump will rise, thus building up pressure in the air chamber and in the filter until the air pressure is equal to the pressure in other parts of the lubricating system, so that on interruption of the operation of the pump the pressure in the air chamber and above the surface of the oil therein will be operative to force the oil through the filter.

The air chamber may be wholly or partly external. to the filter chamber, being arranged at a position between the non-return valve in question and the inlet to the filter, or it may be constituted by a space in the filter chamber itself located at a position above the filter elements therein, or the air chamber may be constituted by an additional member external to the filter chamber and a proportion of the space within the chamber containing the filter elements and positioned above them.

The invention consists particularly in a filter comprising a-chamber in which the filter elements are located, an inlet to the chamber for the liquid tobe filtered and within the chamber at the upper portion thereof a space adapted to provide an air chamber above the level of the filtering elements and an outlet from the chamber for the filtered liquid opening into the filter chamber at a position below the level of the air chamber.

The filter may be of any appropriate form. It may be of the edge filtration type or it may be Great Britain April 3, 1943 a filter in which the filtering elements are constituted by a plurality of relatively thin annular cells having porous walls located about a central drainage or delivery element.

With a filter system in accordance with the invention, every time the engine is started and run, even for a minute or two, a considerable amount of filtered oil must be returned to the engine, the amount depending on the size of the air chamber fitted.

If the engine is run for a considerable time, the operation of the filter ismuch the same as it would be without the air chamber, but even in this case there may be some advantage from the initial high pressure developed when the oil is cold, as this will not now fall off when the oil in the engine is warm but the oil in the filter has not yet warmed up.

The invention will be described further in detail and by way of example with reference to the accompanying drawings, in which- Figure 1 is a view in elevation partly in section;

Figure 2 is a sectional elevation, and

Figures 3 and 4 are respectively views in sectional elevation and plan of a detail of a modified construction.

Figure 5 is an enlarged fragmentary view in sectional elevation of a part of the filter system elements as shown in Figure 2.

The drawings illustrate constructions in which the air chamber is constituted by a space in the filter chamber itself, and in Figures 1 and 2, l is the filter chamber, 2 the inlet thereto, 3 a non-return valve associated with the inlet, 4 being a bell-shaped member providing an air chamber 5 between inner and outer walls 6 and I located above the filter elements 8 which are in the form of a plurality of relatively thin annular cells 9 of known construction located about a drainage element Ill having channelled washers ll within each cell chamber adapted to permit liquid to pass to the drainage element and further unchannelled washers [2 between adjacent cells.

I The central drainage element I0 is in the form of a perforated tube surrounding a rod i3 rigidly engaged in the base of the filter chamber and having about it a collar I4 forming an abutment for the lowermost of the aforesaid unchanneled washers associated with the plurality of cells.

A paper washer I5 is interposed between it and the lowermost unchanneled washer in question and a joint ring i6 is provided between its lower end and the base of the chamber I.

The upper end of the rod is provided with a screw-threaded portion l'l engaging a screw- 1. threaded element 18 furnished with a shoulder Hl between which and the cover 20 of the chamher is a washer 2|.

Below the cover of the filter chamber which is arranged toseat upon -a jointing 'ring ZZ, there is provided aspring'fl which bearsupon'a metal disc 24, between which and a bell shaped element 25 there is located The lower edge of the element 25 is seated on a collar 21 surrounding the drainage element 10. A paper washer 28 is providedbetween the lower edge of the bell and the coIlar Z-kand the latter is seated on top of the 8. The spring 23 operates to force the collar- 27 against the assemblage of the filtercellsto maintain them in liquid-tight contact one Fwitlfi the other. The collar 21 is maintained in fluidtight engagement with the upper portidnof the drainage element by iheans of a sealing ring 29.

The-upper-end of -the-rodl3 has-an aXial 'bore orchannel 30 which" extends into the upper portion of the assemblageof filter-cells 8and which communicates by-means of atransverse' channel or bore-3i withthespace betweenthe drainage tube -H) and the rod +3. *The filter liquid can therefore flow inseries from this space through the channelsSl and-'30, the element '18 'andan outlet G2. The-filter'chamber l, as shown in Fig. 1, is provided with a screw'plug 33 to enable the '-contents'- of the filter chamber to be emptied when necessary for cleanihgand like purposes.

In the operation of the' filter unit shownin Figs. 1 and -2, 'the liquid to be 'filtered, which, according to a "preferred iorm of the invention is the-lubricating oil -of an internal combustion engine, is ---forced by means i of an oil pump into the filter unit through the i-nlet-'line'-2 and the non-return valve -3"-provid'ed therein, "into the filter chamber 1. The-oilin the filter chamber covers the filter elements'8, fiows through the filterin' material to the insi'tiechambers 9 of these elements, then through the openings in washers l I into the space between the perforated drainage-tube ilband the'tie-rod P3. The oil is filtered in passing-through theelements '8, andthefilteretl oil is conducted through the channels 3| and 30, the 161611181113 l8, and-through the outlet 32 to the parts of "the internalcombustion" engine to be lubricated.

The bell-shaped-membentmounted in the upper portion of the'filter-chamber I, above the assemblage of' filtering elements,='acts to'trap-air which isreadilypompressible. As the pressure builds.-up-in thefilter Qha-mber; the air i's'compressed inthe-bel-l d'a's-the oil level-rises therein. Internal combustion'englnes, such as those used in automobiles, --are usually employed for relatively-short runs. When-the pressure isbuiltup in'the filter chamber *l by such a run, and the automobile and the oilpump stop, the filtration carried on ==by the filter unit -continues"b'ecause the non-return valve *3 F prevents 1 release of pressure through the line '2, and" the built-up ain pressure in the bell 4 is available to force=oi1 from the filter chamberp Therefore, after the pump stops, the 1 pressure in "the filter chamber is relieved gradually by the flow of filtered oil through "the outlet-32*, the expansion of the compressed-air in the bell d serving as the motive force for forcingoil through-the filter-and through the-outlet 32. The parts of the combustion engine which arelubricatedbythe *oilpump are therefore covered -withclean filtered oil after the engine stops, 7 7 I I g I Referring to Figures 3 and 4 which illustrate a combined bell and-cover plate-for the filter chamberjaa is asci'ew thraded lioleihto'which a felt washer 26.

assemblage of-filter cells .t "constitute an air chamber, 39

the inlet valve may be screwed and 35 :ther hole through which' the---delivery of the =filt'er will "extend whiIe- =36 and '37 are internal and external walls leaving a space 38 which will being a recess in the element in which may be engaged a jointing washer forprovicling a liquid tight joint between the oover-illustrated'and the body of the filter -chamber which' may be of the form illustrated is a furlo in' Figui es 1 and '2.

- -I claim: 1. A filtercomprising a filter chamber includfing meansdefiriihg an open bottomed air chamber in the upper portion thereof, a vertical as- 3 sihbla g'e of filtering elements mounted in said filter chamber below the level of said air chamher, a central drainage tubeextending vertically through said filtering elements and "adapted 't'o receive filtered liquid therefrom, means --for conducting liquid *from' said drainage tube at the to be-filtered to thefilter'chamber and an liquid -'-from said drainage tube for upper portion of said 'ass'emblag-e of filtering elements, means -'including a spring arrangedin compression between the top inner'side of said filter -=cliafnber "and the top-npper side of-= th'e 5 uppermost filter element of "said assembly of filtering elements for maintainiii'g said assembly in liquid-tight engagement with each other around I said drainagetube, "an inlet including a non-return valve for introducing all the liquid outlet said means ion-conducting Withdrawing filtered liquid from the filter chamber.

- -2. A filtercomprising a 'filter chamber"includcommun-ieating with mg-an open-bottomed bell shaped air chamberin the upper portion thereof, a vertical assemblage of filter-ingelements-mounted in said filter cha n ber'be'low the-level of said air chamber; a central drainage tube-extending vertically through said 0 filtering "elements-* and" providing an outlet-for withdrawing *filtered =liquid and adapted -to-receive' I filtered-liquidtherefrom-,- means "for conducting liquid from-said drainage'element at the upper portion of-=lsaid'-'assemblage of filtering elementaan lnlet line for the-delivery of liquid-ta b'e filtered 'to 'said "filter -chamber; --said' 'inletline including-anon-return 1 valve through whichpasses all thediquidentering the filter chamber" and which is adapt'ed to preventreverse 'fiow of -liqdid, and an-"outlet linecommunicating withsaid eentral' drainage tube for withdrawing filtered liquid from the filter' oliamber.

JGSEPH-AEIEN PICKARD.

niinannnoiiso'i ran June 13; 1933 Klein July 4,1944 

